Don't know ... I just have had a bottle of Scotch by that time ;)

Nope, I speak clearly. I even tried _very_ clear pronunciation (like talking to a person with bad hearing, etc). My wife tried, too. It comes back to playing German Rap and Dance music.

Maybe I have been classified by Amazon and people who are similar to me tend to listen to dance/rap in the evening. No idea. It's just a curious case of a bug. (I switched to piano music since - which works pretty well).

I think its a Homekit to Siri issue. I have the opposite issue, Siri almost always works for me for turning off the lights but the Home app works only half of the time.

The AI might be trying to be "smart" and factor in the time of day when interpreting commands.